1. Field of the Invention
This invention relates to acoustic beacons for objects in oceanic regions and are to be used primarily to indicate the position of boats or other objects present below water, for example, after a wreck.
2. Description of the Prior Art
The locating of wrecks today is a difficult, time-consuming and often expensive task. Often it occurs by chance as a result of fishing operations whereby parts of the wreck are picked up making it possible to determine the position. Active localising of wrecks can be achieved by means of acoustic fish-detection equipment, such as fathometers or sonars, or by way of side-searching sonars. If the position of the object sought after is roughly known, underwater television cameras can also be used.
Hitherto, acoustic beacons or markers have tended to be too expensive and/or too unreliable in operation after an extended period of storage under the demanding conditions prevailing on board ship.
U.S. Pat. No. 3,783,443 (Irick) discloses underwater sound source assemblies which are ejectably mounted on rockets, aircraft, watercraft, precious cargo or any mobile device that may travel over water, to facilitate location and recovery of the device when submerged.
U.S. Pat. No. 3,992,692 (Filer) discloses a self-contained acoustic beacon activated by a sea-water switch for providing an independent method of locating and recovering a floating or submerged recoverable target.